Adrenaline (epinephrine) signalling via the alpha-2 adrenergic receptor has many effects including inhibition of insulin release in pancreas, iinduction of glucagon release from pancreas, contraction of sphincters of the gastrointestinal tract, negative feedback processes in neuronal synapses and stimulation of platelet aggregation. This receptor preferentially couples to members of the Gi class of heterotrimeric G-proteins, leading to inhibition af adenylate cyclase and thereby decreased cAMP levels.